 /*******************************************************************************
  * Copyright (c) 2006, 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.cheatsheets.handlers;

 import org.eclipse.core.commands.AbstractHandler;
 import org.eclipse.core.commands.ExecutionEvent;
 import org.eclipse.core.commands.ExecutionException;
 import org.eclipse.ui.cheatsheets.OpenCheatSheetAction;
 import org.eclipse.ui.internal.cheatsheets.actions.CheatSheetCategoryBasedSelectionAction;

 /**
  * Opens the cheatsheet identified by the parameter, or if no parameter is given
  * opens the dialog that allows the user to choose a cheatsheet.
  *
  * @since 3.2
  */
 public class OpenCheatSheetHandler extends AbstractHandler {

     private static final String PARAM_ID_CHEAT_SHEET_ID = "cheatSheetId"; //$NON-NLS-1$

     public Object execute(ExecutionEvent event) throws ExecutionException {

         String cheatSheetId = event.getParameter(PARAM_ID_CHEAT_SHEET_ID);

         if (cheatSheetId == null) {
             CheatSheetCategoryBasedSelectionAction action = new CheatSheetCategoryBasedSelectionAction();
             action.run();
         } else {
             OpenCheatSheetAction action = new OpenCheatSheetAction(cheatSheetId);
             action.run();
         }

         return null;
     }

 }

